Having worked with both 4k77 and the UHD now, in most cases 4k77 is significantly more tightly cropped than the UHD. So this conversation about cropping is kinda moot.
Maybe in a couple of scenes in Star Wars the cropping varies but in the majority of shots the UHD has more picture info.
In Empire, for many of the Falcon shots were cropped for the SE but these are the only examples of deliberate cropping by Lucasfilm.